Power circuit breakers



May 3, 1955 Filed vFeb. 20, 1952 M. ZUHLKE POWER CIRCUIT BREAKERS 2 Sheets-Sheet l a n a [five/720R 2,7tl7,74tl

NEWER F RUET EREAKERS Marcei 'fiiihilte, fie i n icmensstadt, Germany, assignor to Siemens-Schuctre twerke Alttiengesellschaft, Berlin, Siemeusstadt, Germany, a corporation of Germany Application February 29, 15 52, Seriai No. 272,563

Ciainis priority, appiicatiou Germany March 22, 1951 tion by blast action but much smaller than the quantity 7 needed in conventional tank-type oil breakers.

Oil-poor power breakers are known in a design having a vertically arranged switching chamber and an interrupter contact moving downwardly for interrupting performance. These breakers, compared with other known breakers of an upwardly directed interrupting movement, have the advantage that only part of the oil quantity must be blasted upwardly so that the switching chamber may be given a correspondingly small volume. Besides, the oil separator usually mounted on top of the breaker may likewise have small dimensions; and, since the switch is driven from below, the masses to be accelerated are also smaller.

it is further known to provide breakers of high powerintenupting capacity with two switching chambers of which one is shunted by a resistor and serves to break or depress short-circuit current while the second chamber interrupts only the residual current. The breaker drive operates in such a manner that it first opens the resister-shunted arc gap until a given spacing is reached between the pertaining stationary and movable contacts, and then commences to actuate the movable contact second arc gap. in the known breakers of this kind, the two switch chambers are mounted parallel to each other upon respective supporting insulators. This requires a rather large understructure or Wheeled supporting frame.

Relating to oil-poor circuit breakers with two arc-gap chambers for high-power duty, it is an object of my invention to provide a power breaker whose height and overall dimensions for any given power rating are considerably smaller than heretofore obtainable; and it is also an object to give such a power breaker a doubled voltage rating while requiring only a disproportionately small increase in space requirements.

According to a feature of my invention, the one resistance-shunted arc-gap chamber is mounted so that its axis is vertical or approximately vertical, while the axis of the other chamber extends at an angle thereto. The design is preferably such that the axes of the arc-gap chambers, i. e. the directions of the downward opening movement of the respective switch pins, intersect each other at a point from which the two switch pins spread upwardly away from each other. The two switch insulators enclosing the arc-gap chambers are carried by a common supporting insulator structure. In such a breaker, the switch contact pin pertaining to the resistance-shunted breaker portion for the interruption of high currents performs its circuit breaking movement in a vertically downward direction so that the above-mentioned advantage of the known breakers remains fully secured. On the other hand, the other component breaker portion may readily be inclined toward the vertical without det- States Patent G 0 portion meant-s Farented may 3 1955 riment, as it interrupts only the relatively low residual current so that the oil quantity of the blast is rather small.

In contrast to proposals requiring the two switch chambers to be disposed vertically above one another, a breaker according to the invention affords the advantage of a much smaller height. The angle at which the com ponent breaker of small interrupting duty is inclined toward the vertical is preferably so chosen that the two top terminals of the respective breaker components lie at about the same height. The switch pins of both contact devices are preferably driven from below through a common insulating shaft assembly acting through gear transmissions upon the pins.

According to a further feature of my invention, two such oil-poor breakers are placed side by side on a cornmon base and are combined to form a single power breaker by series connecting the four arc-gap chambers. As a result, the breaker has the double voltage rat ng. When operating the breaker, the two resistance-shunted arc gaps are opened first. Thereafter the two other are gaps are opened when the distance between the movable and stationary contacts of the first-opening arc gaps has reached a given magnitude.

According to a more specific feature of the invention, the two component breakers have their respective inclined switch insulators disposed adjacent to each other and the pertaining two top terminals electrically connected with each other. This has the result that in the circuit-open condition of the breaker of the voltage drop is uniformly distributed over the respective two are gaps.

It should be understood that when referring in this specification and in the pertaining claims to oil, the use of other liquids known for circuit breakers is meant to be included. In other words, the term oil-poor circuit breaker is used to designate a type of breaker design generally known under this term, rather than for the purpose of limiting the invention to the use of any particular liquid.

The foregoing and other features of my invention are apparent from the following description of the embodiments exemplified by the drawings, in which:

Fig. 1 shows a liquid-containing circuit breaker partly by a vertical axial section; and

Fig. 2 is a front view of a circuit breaker composed of two breaker units substantially in accordance with Fig. 1.

The circuit breaker illustrated in Fig. i has a resistanceshunted high-duty portion l. and a series-connected portion 11 for residual power interruption. Portion 1 has a tubular switch insulator with a tubular insert 5, both consisting of porcelain or similar ceramic material. The pertaining interrupter contact device has a stationary contact member 2, and a movable contact memher 3 designed as an elongated switch pin. The arc-gap formed between the two contact members during the interrupting performance occurs within an elastic arcing chamber 4 filled with oil. The chamber is formed by a structure that is axially traversed by the switch pin 3 and is enclosed within the tubular insulator 5'. Shunt connected to the arc gap is a resistor 6. The resistor is mounted on switch insulator l and has its end terminals electrically connected with the stationary and movable contact members respectively. The switch pin 3, in the illustrated embodiment, is connected with the axially displaccable member 7 of an helix or screw type drive. When the shaft of this drive is revolving, the helix member "I and the switch pin 3 move downwardly or upwardly along the pin axis.

The circuit breaker portion ii for interrupting the residual current has an inclined position relative to The interrupting contact device of breaker portion 11 has a stationary contact piece 12; and a movable switch pin 13 as well as an oil filled chamber structure 14 which may be of switch pin 13 is connecteo with of a screw type drive. The are c other structure 14 is disposed within a tub-slur insert A. of a switch insulator Ill.

The two breaker portions are d by a common supporting insulator sbucture it which, the illustrated example, consist of a single so rting column. However, an insuiating structure of di design, for instance, composed of three per be used.

Driving motion is app] type drives through assembly switch pin 3 i is first movem r gears of a 'ertical insulating shaft During the inte g performance, the in the resistance-Jr d breaker portion moved to its ope no *c interrup ug see only after the . ationary contact member 2 has reached a e. closing the cir tit breaker both switch s 3 and are moved pra 'aneously to the closed position. Details of tl pertaining 6 u for obtainthe desiiv 'al swi i tion are not illustrated as they may be si ti drive means of known brearers.

The two switch portions and 11 are joined with each other and with the supporting i. sulator lit by a metal housing 22 located at the intersection of the two switch pin axes. The above-mentioned screw members 7 and l? as well as the transmis on gz 's Z1 con ecting the screw drives with the sh sly are enclosed 'n the housing 2.2. lvlountcd on the given I? k tive tops of the switch insulators l and 1.1 oil separators g and These separators lie 1 ely at the same The breaker terminals ti and i3 or connect; of the stationary contact members to the line to are likewise located at about the same two are gaps are electrically sehc the metal housing 2 nected with the two The insulating 3- base or it c compressed air as well as the ireans for h each other through urn is conductively eonmounted on a wheeled it contains a tank for driving the shaft transmission by the compr ssed air.

In the embodiment illustrated in Fig. 2, two circuit breakers according to Fig. l are combined to form a breaker for the double voltage. The two component breaker units are denoted by Sit and as respectively.

each unit has a high-powe breaker portion 31 or 31 with a shunt re tor or 32, t id s r s-connected breaker portion or 33' for the inte ruption of i residual current. The breaker portions a 33 are inclined toward each otter and are so arranged that their respective terminals 1 3 13 are adjacent to each other. The terminals and 28 are interconnected so that all four interrupter gaps of the composite breaker are series connected W1 n the circuit line to controlled is attached to the top termimale 8 and 8' of the respective breaker portions 33. and 31. The movement or" all four switch pins is in the downward direction in accordance with the design shown in Pig. 1. The two breaker portions of each unit are carried by a common insulator 34 or 34', and each breaker unit has a shaft assembly 35 or 35 as described previously in coniuncti n with Fig. l.

The two units are mounted on a wheeled base structure. The middle portion 5 study of this disclosure that circuit breakers acco 'ng to my in ention may be modified as regards various details wi hout depar .g from the essence of the invention and within the scope of the claims annexed hereto.

I claim:

1. An oil-poor circuit breaker, comprising two successively operating breaker portions electrically seriesconnected with each other for reducing overload current and interrupting the residual current respectivel each of said breaker portions having an elongated hollow insulator forming an arc chain and containing liquid in said chamber, a fixed contact and a movable contact disposed in said chamber, said movable contact being separable from said fixed contact in the axial direction of said insulator; said one breaser portion for reducing overload current having a shunt resistor connected across said contacts and having said insulator extend in a subally vertical direction; said insulator of said other breaker portion extending at an acute angle upward from the bottom or" said one breaker portion; and a supporting insulating structure carrying both said breaker portions.

2. An oil-poor cir uit breaker, comprising two breaker portions, one for reducing overload current and the other for subsequently interrupting the residual current, said two breaker portions being electrically series connected with each other; each of said breaker portions having a tubular insulator forming an arc chamber and containing a quantity of liquid for are extinction, a stationary contact and a movable switch pin disposed in said chamber, said switch o n being normally in circuit-closing engagement with said stationary contact and being downwardly separable from said stationary contact in the axial directic-n of said insulator; an operating mechanism connected with said two switch pins for moving said switch pin of said one breaker portion prior to moving said other switch pin; a shunt resistor connected across said stationary contact and said switch pin of said one brer. r portion; said insulator of said one breaker portion being axially shorter than said other insulator and having a substantially vertical axis, said other insulator having axis extending at an acute and upwardly open angle to said vertical axis; and a supporting insulator structure common to said two switch insulators and being joined therewith near the intersection of said axes.

3. An oil-poor circuit breaker, comprising two bre ker portions, one for reducing overload current and the other for subsequently interrupting the residual current, each of said breaker portions having a tubular insulator forming an arc chamber and containing a quantity of liquid for are extinction; a stationary contact and a movable contact disposed in said chamber, said movable contact being downwardly separable from said stationary contact in the axial direction of said insulator; a shunt resistor connected across said stationary contact and said movable contact of said one breaker portion; an operating mechanism connected with said two movable contacts for separating said movable contact or" said one breaker portion prior to separating said other movable contact from the respective stationary contacts; said one insulator of said one breaker portion being substantially vertical, said other insulator being axially longer than said one insulator and being joined with said one insulator at th foot end of the latter and extending therefrom upwardly at an acute angle; said respective movable contact devices being electrically series connected with each other, respective terminal means disposed on top of said two insulators at substantially the same height and connected with said respective stationary contacts; and a supporting insulating structure on which both said insulators are mounted.

4. in combination, two circuit breakers according to claim 3, a base structure, said supporting structures of said respective breakers being mounted on said base structure and extending vertically upward therefrom in spaced relation to each other; said respective other insulators of said two breakers being upwardly inclined toward each other and having their respective terminal means juxtaposed to each other at substantially the same height above said base, and said latter two terminal means being electrically joined with each other References Cited in the file of this patent UNITED STATES PATENTS 2,556,056 Bally June 5, 1951 5 FOREIGN PATENTS Great Britain Apr. 20, 1939 France Oct. 30, 1939 

